President Obama has tapped a former Army general to lead the Transportation Security Administration, sources have told CNN.

Obama plans to nominate Robert A. Harding, a retired major general with 33 years in the Army, to become the TSA administrator, sources said. Department of Homeland Security Secretary Janet Napolitano will announce the nomination Monday with Harding by her side, according to one administration official.

“The TSA administrator is the most important unfilled post in the Obama administration,” one administration official said. “Mr. Harding has the experience and perspective to make a real difference in carrying out the mission of the agency.”

“If there was ever a nominee that warranted expedited, but detailed, consideration in the Senate, this is it,” the official said.